In Julius Caesar, the carpenter and the cobbler take a day off of work to celebrate Caesar's entrance into Rome following his victory in a civil war against another Roman general. As the Cobbler tells Flavius and Marullus:
make holiday to see Caesar and to rejoice in his
triumph. (Act 1.1.33-35)
Flavius and Marullus are upset by this, they say, because Caesar has only defeated another Roman, not conquered an enemy. They want to know who Caesar brought back to Rome who will pay monetary tribute to the city after having been conquered. The implied answer is no one, of course, since it was only a civil war. The two chase away the commoners and "disrobe the images" (line 69), or take off the ceremonial scarves honoring Caesar from Rome's statues.
I'll let another editor handle what happens to Flavius and Marullus because of their actions, if that's what you're asking. There are no slaves in the opening scene, though. The cobbler and the others are commoners, but they're not slaves, and Caesar doesn't do anything to them. Flavius and Marullus are the ones who are punished.